Photos of the poop?
Are they molting?
The photos you posted a week ago, I see no lethargic looking hens. If they are in molt, they likely will not be producing eggs and they can be a bit slower, they are focusing on growing feathers. Weather changes, time of year, etc. also can affect they...
What are you feeding that you think they would be malnourished?
At this time of year, they are probably molting. In the photos I don't see anything to really indicate sunken eyes, bubbly eyes or mucous which are sometimes seen with respiratory illness.
Looking like choking, do you provide...
What is the antibiotic the vet prescribed?
In one post you say vet suggested "Respiratory Infection" do your hens have any symptoms like coughing, sneezing, mucous, facial swelling, wheezing, etc. that would indicate respiratory symptoms?
Please post photos of your birds!
They all have fevers...